You get these
http://www.ebay.com/itm/10-Pcs-2-54mm-Pitch-Female-14-Pins-Flat-Cable-IDC-Socket-Connector-Black-/281021184180?
$3.79 for 10pcs (which comes to about $0.75 a pair)
The ribbon cable is just clamped by the connector, no individual soldering or crimping.
Then buy the ribbon cable, 3 foot is $3.60 from this seller, for example
http://www.ebay.com/itm/36-Conductor-Ribbon-Cable-Rainbow-Colored-and-Laminated-3-100-ft-/180938840320?pt=LH_DefaultDomain_0&hash=item2a20cb9900
I know what you're thinking, the connector is 10P and the ribbon cable is 36P... yup, nick one end, and pull apart into 10P each... now you have 9 foot total of 10P ribbon cable for $3.60!
So that's $1.15 cost each and you get 9pcs of 12" IDC cables (10P).
For the crimping tool, you can buy a special tool, but a groove joint pliers will do the job just as well. (Just wrap the connector with cloth or tape the jaws of your pliers so it wouldn't mar the plastic connector).
or get one of these if you'll be doing lots and lots of cables of varying widths.
http://www.ebay.com/itm/IDC-Ribbon-Cable-Crimping-Tool-with-Attachment-17195-4-/390510231747?pt=US_Cabling_Tools&hash=item5aec3940c3